Annealingmodification of MXene films with mechanically strong structures andhigh electrochemical performance for supercapacitor applications

XinZhao*, Zhe Wang, Jie Dong, Tao Huang, Qinghua Zhang, Lili Zhang*

Journal of Power Sources, 2020, 470, 228356.

https://doi.org/10.1016/j.jpowsour.2020.228356

Two-dimensionaltransition metal carbides and nitrides (MXene) have shown outstandingperformances in electrochemical energy storage, but theirinvestigations of both mechanical and electrochemical performance forstructural power systems are lack of being discussed. In this work,modified MXene films with mechanically strong structures and highelectrochemical performance are obtained via directly annealingstrategies. Due to the beneficial chemical composition on the surfaceand the structural variation under appropriate annealing treatmentconditions, the modified Ti₃C₂TxMXene electrode can deliver an ultrahigh volumetric capacitance of1590 F cm⁻³with a gravimetric value of 442 F g⁻¹at 0.5 A g⁻¹,a good rate capability of 1030 F cm⁻³at 20 A g⁻¹,a cycling stability with a retention of 95.4% after 5000 cycles inthe acid electrolyte and a high tensile strength of 32 MPa,demonstrating its great potential as a multifunctional electrode forstructural energy and power systems. The influences of differentelectrolytes on the intercalation-induced electrochemical process ofmodified MXene films were also probed. Furthermore, the assembledsymmetric supercapacitor with the modified Ti₃C₂TxMXene film demonstrates a favorable volumetric energy density of 15.2Wh L⁻¹and a power density of 204.8 W L⁻¹.